RESUMO
To generate temporally controlled targeted somatic mutations selectively and efficiently in skeletal muscles, we established a transgenic HSA-Cre-ER(T2) mouse line in which the expression of the tamoxifen-dependent Cre-ER(T2) recombinase is under the control of a large genomic DNA segment of the human skeletal muscle alpha-actin gene, contained in a P1-derived artificial chromosome. In this transgenic line Cre-ER(T2) is selectively expressed in skeletal muscles, and Cre-ER(T2)-mediated alteration of LoxP flanked (floxed) target genes is skeletal muscle-specific and strictly tamoxifen-dependent. HSA-Cre-ER(T2) mice should be of great value to analyze gene function in skeletal muscles, and to establish animal models of human skeletal muscle disorders.
Assuntos
Actinas/genética , Regulação da Expressão Gênica , Integrases/genética , Camundongos Transgênicos , Músculo Esquelético/embriologia , Músculo Esquelético/crescimento & desenvolvimento , Animais , Antígenos CD/genética , Antígeno CD24 , Linhagem Celular , Cromossomos Artificiais , Modelos Animais de Doenças , Escherichia coli/genética , Imuno-Histoquímica , Glicoproteínas de Membrana/genética , Camundongos , Mutagênese , Receptores de Estrogênio/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
X-linked adrenoleukodystrophy (X-ALD) is a severe neurodegenerative disease caused by loss of function of the peroxisomal transporter ABCD1 (ALD), which results in accumulation of very long chain fatty acids (VLCFAs) in organs and serum, central demyelination and peripheral axonopathy and Addison's disease. Knockout of the ALD gene in the mouse (ALD(-)) results in an adrenomyeloneuropathy-like disease (a late onset form of X-ALD). In the present study, we demonstrate that axonal damage occurs as first pathological event in this model, followed by myelin degeneration. We show that this phenotype can be modulated through expression levels of an ALD-related gene (ALDR/ABCD2), its closest paralogue and a target of PPARalpha and SREBP transcription factors. Overexpression of ALDR in ALD(-) mice prevents both VLCFAs accumulation and the neurodegenerative features, whereas double mutants for ALD and ALDR exhibit an earlier onset and more severe disease (including signs of inflammatory reaction) when compared with ALD single mutants. Thus, our results provide direct evidence for functional redundancy/overlap between both transporters in vivo and highlight ALDR as therapeutic target for treatment of X-ALD.